This workout uses a variety of HIIT protocols to challenge the upper body and core. HIIT stands for high-intensity interval training, which refers to the short bursts of intense exercise alternated with low-intensity recovery periods. HIIT can burn a lot of calories in a short amount of time and has shown to help with fat loss. It can also help with exercise plateau! This workout uses mainly body weight exercise to train the core and upper body. Equipment needed: yoga mat and resistance band.